1. Field of the Invention
This invention relates to a sieving device and a sieving mesh screen, and more particularly to a sieving device capable of efficient sieving by force of vibrations generated by vibration generating means, and a sieving mesh screen easily demountably mounted in the sieving device.
2. Description of the Prior Art
Japanese Unexamined Patent Publications Nos. 2001-129483, 2000-135474, 2000-312860, HEI 11-128842, HEI 10-76229, and HEI 09-141205 disclose conventional sieving devices having mesh screens, which are vibrated by force of vibrations generated by an electromagnet, air piston, electric motor, ultrasonic vibrator or the like to sieve flour or other particulate materials.
The conventional sieving device is generally provided on its lower portion with a vibration generator, on its upper portion with a sieving receptacle having a bottom member, and with a mechanism for discharging granulated or floury particulate material sieved through the sieving receptacle. The particulate material sieved by the conventional sieving device once falls into a first collecting portion, namely, the bottom of the sieving receptacle, and moves from the first collecting portion to a second collecting portion, e g. a collecting container. Thus, the sieved particulate material agglutinates to dump while moving from the first collecting portion to the second collecting portion, consequently to diminish the purport of sieving.
Furthermore, since the sieved particulate material is discharged to the outside of the sieving device, the conventional sieving device disadvantageously necessitates a wide space for installing the collecting container or the like for receiving the sieved particulate material discharged from the device. Besides, the conventional sieving device cannot prevent the sieved particulate material from getting out of the collecting container or scattering around. Therefore, the conventional sieving device is not applicable to a kitchen with a confined space or other ambiences requiring sanitary precautions.
There has been another prior sieving device having a mechanism for removing the particulate material staying behind on a sieving screen, consequently being inevitably increased in size on the whole. Thus, this conventional sieving device requires a wide installation space and therefore is unfit to use in a confined narrow space
In the conventional sieving devices noted above, vibration generated by the vibration generator mounted on the lower portion of the sieving device is transmitted to the mesh screen supported by a plurality of springs. Thus, the vibration generated by the vibration generator is not efficiently transmitted to the mesh screen due to difference in vibration transmitting routes formed by the springs. Moreover, the vibration is absorbed by the springs to decrease the efficiency of sieving and slow down the sieving speed. In order to increase the efficiency of sieving the particulate material, the size of the device including the vibration generator and power source is inevitably increased.
There has been yet another prior sieving device provided on its side portion with a vibration generator for giving lateral vibration directly to a mechanism with a mesh screen, Since the mechanism with the mesh screen in this prior device is suspended through means of a connection member and receives at one part thereof the vibration from the vibration generator in the lateral direction, the vibration is attenuated by the connection member to decrease the efficiency of sieving and slow down the sieving speed like the aforementioned prior sieving device.
Furthermore, in the aforementioned prior sieving device of large size, which is provided fixedly with the mesh screen or mechanism having the mesh screen, removal of the particulate material left on the mesh screen, cleaning of the mesh screen and installation of the sieving device cannot easily be carried out. When the particulate material left on the mesh screen is removed to clean the mesh screen, the mechanism including the mesh screen has to be detached from the device body. Even if the removal of the particulate material left on the mesh screen is easily carried out, it is difficult to clean and attach the mesh screen onto the device body.
In the sieving device provided on its side with the vibration generator for imparting the vibration directly to the mesh screen in the lateral direction, the component parts such as the mesh screen, blade member and connection member of the sieving device should be disassembled to remove the particulate material left on the mesh screen, dean the mesh screen and assemble the components parts. This turns out to be a very troublesome chore.
In addition, the prior sieving device entailed a disadvantage such that driving means including a motor and a piston inevitably generates dreadful noise and needless vibrations in operation. These undesirable vibrations could not substantially be prevented. Thus, the prior sieving device was susceptible to mechanical trouble and difficult to maintain.
In Japanese Unexamined Patent Publications Nos. HEI 11-114498, HEI 11-347492, HEI 06-233617 and HEI 06-233618, there are disclosed conventional sieving mesh screens for sieving particulate materials such as flour, which are driven to vibrate by a vibration source such as an electromagnet, motor and ultrasonic vibrator.
The prior art sieving mesh screens aim at increasing the efficiency of sieving, preventing clogging and increasing the durability. The mesh screen disclosed in Japanese Unexamined Patent Publication No. HEI 11-114498 is formed by crossing and overlapping wires each other and welding the wires so as to increase the efficiency and speed of sieving. The conventional mesh screen disclosed in Japanese Unexamined Patent Publication No. HEI 11-347492 is made by weaving compound fiber to form a rolling surface.
Also, the sieving mesh screens in other prior art are by and large made by crossing and welding wires, weaving wires or integrally molding into one body having a required number of meshes.
The prior sieving mesh screens made by crossing or weaving the wires have corrugated surfaces formed by the wires thickly overlapping each other and supported by a frame thickened by the overlapping wires. The vertical interval of the upper and lower wires of the mesh screen thus corrugated is smaller than the diameter of the wire and the thickness of the frame, so that unevenness of such a planar mesh having the vertical interval of the wires cannot Increase the number of meshes in the mesh screen of the same shape in the identical terms. Thus, there is a limit to the prior sieving mesh screen having the ragged wire surface in increasing the sieving speed and sieving efficiency. Besides, the prior sieving mesh screen requires specific materials and must be molded precisely, consequently to increase the manufacturing costs incurred and make the manufacture thereof difficult.
An object of the present invention is to provide a sieving device provided with a mesh screen which can be attached and detached so as to facilitate removal of particulate material remained on the mesh screen and cleaning of the mesh screen, which sieving device is capable of preventing the particulate material while being sieved from getting out of the collecting container or scattering around, being installed even in a confined space requiring a sanitary condition, producing sieving vibration with a relatively small power source and efficiently transmitting the vibration to the mesh screen to perform sieving of particulate material at a high speed with high efficiency, preventing coagulation and agglomeration of particulate material, and suppressing noises generated by itself.
Another object of the present invention is to provide a sieving device having a mesh screen capable of eliminating the shortcomings of the mesh screen disposed in a conventional sieving device, and increasing the speed and efficiency of sieving particulate material.
Still another object of the present invention is to provide a sieving device having a high-efficiency mesh screen, which can easily be manufactured at a lower cost.
To attain the objects described above according to the present invention, there is provided a sieving device comprising a frame body, a feeding unit mounted on the upper portion of the frame body for feeding particulate material vibration generating means mounted on the middle portion of the frame body for imparting vibration to a pair of vibration members, a mesh screen detachably attached to the vibration members, and a reception unit mounted on the lower portion of the frame body for receiving the particulate material.
The aforementioned sieving device can prevent the particulate material while being sieved from getting out of the collecting container or scattering around, and be used even in a confined space requiring a sanitary condition. In the sieving device, the vibration generated by the vibration generating means can be transmitted to the mesh screen with high efficiency at a high speed so as to carry out effective sieving of the particulate material, and further prevent coagulation and agglomeration of the particulate material.
The paired vibration members are fixedly connected with each other through a joining member. This structure brings about the synergistic effect of the vibration members and joining member, so that the effective vibration can be obtained with a small vibration source and efficiently transmitted to the whole of the mesh screen, thereby to carry out sieving of the particulate material quickly with high efficiency.
The vibration members each have a concave portion in the respective opposite surfaces, so that both ends of the mesh screen can be removably fitted thereinto. With this structure, the mesh screen can easily be dismounted for cleaning up.
In another embodiment of the invention, the vibration member comprises a base body supported by a support member, vibration transmitting members projecting from the base body, and joining member secured on the tip ends of the vibration transmitting members, and the aforementioned frame body is provided in both side portions of the middle portion thereof with a hollow portion having inner holes so as to contain the vibration generating means and vibration members in the hollow portion. The vibration transmitting members protrude through the inner holes in the hollow portion so as to secure the mesh screen onto the joining member on the vibration transmitting members protruding through the inner holes. This sieving device makes it possible to prevent the sieved particulate material from getting out of the collecting container or scattering around, consequently to facilitate cleaning and maintenance of the device,
In this sieving device, the vibration generating means may be formed of an electromagnetic means, and the vibration member Is supported by a flexible support member having vibration members to be attracted to the electromagnetic means. This mechanism can suppress noises generated in sieving operation and facilitates cleaning and maintenance of the sieving device.
The vibration generating means and support member may be mounted on a mount frame placed on vibration absorbing means. According to this mechanism, noises and undesired vibrations generated in operating the sieving device can be suppressed.
On the frame body, a moving member may be placed for carrying the reception unit in a vertically movable state.
The sieving device may further comprise a press plate supported by the frame body in such a state that one end of the moving member is engaged with the tip end of the press plate.
Further, the sieving device may be provided with a lock mechanism for securing the press plate in position, so that the reception unit can easily be mounted on the frame body and the distance between the mesh screen and the reception unit can be reduced. Consequently, this mechanism makes it possible to prevent scattering, coagulation and agglomeration of the sieved particulate material.
The mesh screen may be formed of a bottom member having a rugged surface and a side member. The bottom member of the mesh screen may be formed in a corrugated shape. The corrugated screen mesh may be formed in the shape of a quadrangular pyramid.
By forming the mesh screen in various shapes as described, the bottom surface of the mesh screen can be increased in area, thus the number of meshes. Therefore, the particulate material being sieved is brought in sufficient contact with the mesh screen without modifying the configuration of the mesh screen, so that the particulate material can be prevented from agglutinating or gathering in clusters. Furthermore, the sieving of the particulate material can be efficiently carried out at a high speed with high screening power. By using the corrugated mesh screen, the sieving efficiency can be more increased. The mesh screen in the sieving device of the invention can readily be manufactured from any sort of material without using specific material, the manufacturing cost for producing the sieving device of the invention can be decreased.
Other and further objects of this invention will become obvious upon an understanding of the illustrative embodiments about to be described or will be indicated in the appended claims, and various advantages not referred to herein will occur to one skilled in the art upon employment of the invention in practice.